Pixelated displays are typically based on liquid crystal displays (LCDs) for displaying images and videos. Each pixel of the LCD is switched on and off using one or more transistors. The transistors are typically manufactured using complementary metal oxide semiconductor (CMOS) technology or thin film transistors (TFTs) and are formed on a backplane of the LCD device. However, integrating the backplane in the LCD device increases the thickness of the LCD device. Further, the LCD device includes a backlight system to generate light. The light is then incident on color filters for generating red, blue, and green lights. Thus, the LCD device becomes bulky due to integrating the backplane, backlight, and color filters on a common substrate.
Due to the above-mentioned disadvantages with conventional LCDs, vertical cavity surface emitting lasers (VCSELs) are being utilized as light emitting devices in pixelated displays. VCSELs are further utilized in various applications such as optical fiber data transmission, broadband signal transmission, laser printers, and applications of the like. VCSELs are monolithic lasers that include a resonant cavity, and are often fabricated using epitaxially grown structures of III-V semiconductors that are common to III-V transistor structures. The resonant cavity is realized between two distributed Bragg reflector (DBR) mirrors that are formed at the top and the bottom of the resonant cavity. In contrast to LEDs that are typically limited to an efficiency on the order of approximately 10% and yield incoherent light output, VCSELs can have efficiencies of approximately 40% with a highly collimated emissive light output.
Photon energy up-conversion is a process of sequentially absorbing two or more incident photons by nanoparticles, leading to an emission of light at a wavelength shorter than the wavelengths of the incident photons. Typically, lanthanide doped nanoparticles and semiconductor nanoparticles are used in applications for photon up-conversion. VCSELs emit light at specific wavelengths that can be modified using photon up-conversion. In the case of VCSELs that emit at wavelengths in the range of 900-1600 microns, for example, photon up-conversion can lead to output from these devices in the range of wavelengths in the visible light range.
Further, co-integration of VCSELs with monolithic transistor structures enables the control electronics for addressing individual pixels without the requirement for a backplane.
Thus, there is a need in the art for a pixelated light emitting device that can output wavelengths in the visible range without the need for a backplane.